Tool reciprocating device



1952 E. E. MARTIN 2,618,107

' TOOL RECIPROCATING DEVICE Filed Aug. s, 1949 2 sg1EE'rs-sl-1EET 1 IN VEN TOR.

ATTORNEY.

Patented Nov. 18, 1952 rep: STATES PATENT OFFICE Earnest E. Martin,Pasadena, Ga lif assignorto AlmaA. Hutchins, Pasadena,v Calif.

Application August i=6, 1949, Serial Nm 1105521"- 19 Claims! Cl; 51-170) This. invention relates. generally to improved toolreeiprocatihg:apparatusy-and. particularlyi'to fluid. pressure. actuatedmnits'adapted; .for. use as portable: sanders,.filing.rdevices, .za-ndthedike.

Asx'will; appear, devices embodying; the. invention-..are-:-especia1lycharacterized by. aoapacity fora veryz-hi-gh. speed. reciprocation overan: extremely .longmuseful :life and with'little. or no necessity forrepair for; replacement of parts. Such. length or life; is: attained:as: a result; of several :distin'ctiveieatures zservinggto permit-theuse of relatively few moving parts so constructed and interrelated astoreduce wear to :a minimum.

.Inrar fiuidpressure actuated tool of. the present charswter, the. powerpiston. and. iits. associated fiuidcontrol. valves are 'usually.farmore. susceptibleto wear fthanxanyxof. the otherparts; Further, veryslight wear of the piston or valvesehasga relatively great eii ect. onthe. operating ;efiici ency of. the device. Consequently, .a particularobject of. theinventionis toprovide a. piston andvalvearrangement.;adap'ted. for.:efiectivexoperation and yetsozdesigned as:torbe'eomparatively free from wear. under normal use; For thistpurp'ose', I preferably formthe piston itselfpf: a novel ad'es'ign tonbe at. all times. in relatively light. engagement with. the cylinderWall, whileneverthelessi'lfoifm inganuadequate fluid: retaining? seal,Particularlycontemplated', in.:this connecti'on, is .a piston composed.of: 'wear tresistant': rubber-or similar resilient material;

Toiurther reduce-piston wearsand to prevent appreciableivalvewear;;.1:employ a single -unitary piston and valve assembly. adapted"for. axial movement: as "a unit: within a cylinder. bodyandsoamountedasrto lie-substantially free; of any transversethrust-'againstz'the body. In accordance "with. the: invention, .thispiston: and. valve unitrcompri'sesza single? piston having a. pair ofrods extending: axially in opposite directions. The rods. themselvespreferably serve as valves to:-..aItemately admit pressure-fluid toopposite sides of the piston. Transverse thrustion a the piston "andvalve unit is: prevented. by mounting a movable toolxcarryingisectionof:the device to. its: handle section by means entirely independent: ofthe: piston and. valves. That. is, the piston and valves; do. not..-in.any sense guide the two sectionsiafor relative. movement; Preferably,the-ztwozsections are "moi/ably interconnected by providing one: with.rotatablebearings engageablewitha pair; of tracks on'ithe other section.As: will appeanxthe; bearings may be arranged in novel 'ofiset'xrelationto minimize their wear during operation. oritherdevicet In certainsituations, it is desirable towsuppl-y. a liquid... usually water. tothe surface being sanded orrotherwise. treated: by: a reciprocatingtool. additionalefeatureof'this invention 'is to provide .for; the.discharge of; such a: liquid through the-two sectionsuof thepresentdevice to i a location immediately adjacent.- the :surface being worked:on.

Elie-above and further featuresea-nd objects of the present. invention.will-- be .better understood from. the following detailed descriptionof, the typical: embodiment illustrated. the accords pany drawings-1mwhich;

Fig:..Lis a perspectivevviewof. a sand-lngdevioe embodying theinvention;

Fig; 2 is:a..perspective view :of. the: power cylinder of the sander':show-n 1;

3 is an enlarged. vertical-section taken along the longitudinal. centralaidsiof-the device;

Figs. 4 and 5 are transverse sectionstakenason lines '44-.and 55,respectively otH-Eigr 3.;

Fig. 6 is a .horizontal-=.section through: the handle, partly brokenaway,: taken on linefi -fi of Fig. 3.;

' Fig 7 is a plan viewer the.waterrsealingipads Fig. 8 is a plan view ofthe shoe cushion taken online- 8-8 of Figs 3;.

.Fig. 9 is-adetail view showingpthe'relation between thev cylindercarriedwheels and-the shoe carried :tracksor guides; s

Fig. 10 is -an enlarged fragmentary section through the shoepadtaken online Hi -[lei Fig, 8; and

Fig. 11 is an enlarged fragmentary view ofathe piston showing, inexaggerated form, .itstdeformation during. powered displacement.

The. illustrated fluid. operated sanding. device comprises essentially.a handle III, a cylinder. unit generally indicated atfltl and rigidlycarried by the..handle, a sho.e.- L2 guided-.by bearings or rollers I 3.on-the cylinder .for reciprocahmovement relative tothehandleand.cylinder and annitarypistonand valve assemblyv 14 mounted for axialmovement-withinthe cylinder and-beaning. against the: shoe to effect Iits powered reciprocation.

The cylinder: u-nit eomprisesa block or body I5 containing an innercylindrical bore-1d and having. the upper portions ofits side wallstapered at I! for engagement with the. -.l rai1 :l-le;Two-:setsofrollers I3 are carried by. the cyiin-der body at its oppositesides; each roller fleeing 2mtatably mounted. by an individualstub'shaft H embedded: withinv the cylinder body; nsi'iseen best in Fig;9., the central roller on each-side is- 3 slightly higher than the twoend rollers to achieve a purpose which will appear later.

A tubular liner I9 is received within bore l6 of the cylinder body, anditself presents a smooth bore 20 for receiving and engaging the piston.The outer surface of this liner contains a central annular recess 2|cooperating with bore I6 of the cylinder body to form a water jacketabout the cylinder walls. -At its ends, liner l9 contains a pairof'plugs or cylinder heads 22, each having an upwardly extendingpressure fluid inlet passage 23 and a downwardly extending exhaustpassage 24. As seen in Fig. 3, the cylinder body and liner 19 have upperopenings 25 registering with passages 23 in the cylinder plug, and lowerdischarge openings 26 registering with plug discharge passages 24. Eachplug 22 has a central axially extending bore 21 containing a tubularbushing 28 having valve slots or openings 29 and 30 communicating withpassages 23 and 24, re-

spectively.

Handle has a recess 3| in its under side for reception of the cylinder,the recess having tapered side walls 32 engageable with surfaces 11ofthe cylinder bore. Screws 56 extend downwardly through the handle andinto the cylinder body to secure these two parts of the device rigidlytogether and form what is referred to in the claims as the handllesection. As seen in Fig. 6, the handle contains a central longitudinallyextending air inlet passage 33 having an enlarged forward portion 34, inwhose forward end inlet fitting 35 is threadedly received. Ball valve 36is normally urged by spring 31 to close the air inlet passage byengagement with tapered valve seat 38. As seen in Fig. 3, ball 36 may bemoved away from its seat to open the air inlet passage by-downwarddisplacement of valve stem 39 upon depression of valve handle 46. I

Referring again to Fig. 6, the handle contains a water inlet passage 4|at one side of air inlet passage 33 and normally closed by springpressed ball'valve 42. This ball is adapted for movement away from itsseat by downward movement of a valve stem 43, corresponding to stem 39-in the air system. r a

The air inletfitting 35and a corresponding water inlet fitting 43 passthrough a pair of openings in plate or bracket 44 to rigidly retain thatplate in the illustrated position against the-handle. fValve handle 40is pivotally mounted to plate 44 by pin 45, and serves upon depressiontosimultaneously open the air and water inlet 'v'alves. "'Air inletpassage 33 in the handle communicates through'a pair of spaceddownwardly extending branches 46 with the two air inlet passages 23 -in'the cylinder plugs. Tubular elements 4'! are received within the lowerend of inlet passage branches 46 and extend downwardly through thecylinder block and liner and into the upper end of passages 23 in thecylinder plugs to interlock the plug, liner, and cylinder in theillustrated-positions relative to the handle. Elements 4'! arevertically located by their annular flanges 48. O-rings 49, extendingabout elements'41, are clamped between the handle and the cylinder bodyupon tightening of screws 50 to form a seal preventing any air leakageat that location.

Water inlet passage 4| in the handle extends downwardly at tocommunicate through tubular element 52 and O-ring 53 with passage 54 inthe cylinder body leading to the annular recess or water jacket 2|.Water is discharged from 4 jacket 2| through two pairs of angularlyextending passages 55 leading toward the opposite sides of bottomsurface 56 of the cylinder body.

Shoe 12 has a rectangular base portion 5! presenting upwardly projectingside flanges or walls 58 merging near the ends of the base intotransversely extending flanges 59. Immediately at the inside of eachside flange 56, the shoe removably carries an inwardly facing U shapedtrack or channel guide 60 having upper and lower opposed walls 6| and 62between which rollers 13 of the cylinder body are received. Upper walls6! of the tracks extend beyond the sides and hottoms of the tracks forattachment to the shoe by screws 6621. Due to the vertically offsetrelation of the center roller at each side of the cylinder body withrespect to the two end rollers, the center roller engages only upperwall 6| of the track while the other two rollers engage only the lowerwall (see Fig. 9). As will be understood, such an arrangement preventsthe excessive wear of both rollers and track which would occur if eachroller simultaneously engaged both of the opposed track walls. Thetracks are preferably formed of hard resilient metal and the distancebetween the upper and lower track walls is preferably slightly less thanthat required to accommodate the roller assembly. Consequently,each-track must be slightly deformed upon assembling the device in amanner assuring against 'any'looseness in the shoe mounting, even'afterconsiderable wear. I

Shoe l2 carries a pad 63 on its under surface, about which is retainedthe sanding paper or cloth 64. Water discharged through passages 55 atthe bottom of the cylinder body passes through elongated openings 65 inthe shoe to be laterally directed by channels 66 in the upper surfaceofpad 63. From the outer ends of channels 66, the water is dischargeddirectly onto the work im mediately adjacent the location being sanded.To direct the water downwardly without leakage from passages 55 in thecylinder into openings 65 in the shoe, I provide a sealing element orpad 61 (see Fig. '7) received between the opposed horizontal surfaces 56and 66 on the cylinder body and shoe respectively. Pad 67 has twopairs'of elongated openings 69 along its sides corresponding to openings65 in the shoe, and presents two upwardly projecting rectangular beads10 each extending about one of the pairs of openings 69. These beadsengage surface 56 of the cylinder body to form a seal directing all ofthe. water downwardly through opening 65 and channels 66. Air frompassages 24 in the two cylinder plugs discharges toward the ends of thedevice byflowing between the two rectangular beads.

Each end wall or flange 59 of the shoe has a central portion Hprojecting upwardly above the level of the side flanges and forming, inits inner surface, a vertically extending straight sided slot or recess12 for reception of the piston rod. Each of these upwardly projectingportions '1! of the shoe carries at its outside a clamp 13 including apivoted handle section 15 pivotally carrying a paper engaging section16'. As will be understood: upon downward swinging movement of one ofthe clamp handles 15, section 16 of the clamp en.- gages the paper orcloth 64 to tightly clamp. it against one of the cushions 11. Thesecushions are themselves carried at the ends of the shoe between walls 59and a pair of end flanges 18.

The piston and valve assembly. I4 includes a single piston 19 formed ofrubberor similar resilient material and carried centrally ofa pistonamnion rod 80 "through finned sleeve. 94, to which-the.

piston is bonded. As seen in Figs. 3 and 11, the piston has; an annularrecess or groove 8! in its outer surface, and atieither side of thegroove, formsa pair of axially spaced annular beads 82 engaging thecylinderwall. Each of the beads 82 is of circular cross section exceptatits point of'connection to the bodyof the piston. The two side facesof the .pistonhave. corresponding cavities 83 extending. axiallyinwardly a .substantial distance beyond the outer .edge I82 of the.corresponding. bead 182.. Thus, the beads project both radially andaxially from the body of the piston. As aresult of this pistonconstruction,

thebeads always engage the cylinder wall with.

only the relatively light. force required to form an'adequate'seal andnever. with the undesirably tight. engagement. of most pistons andrings. Specifically, assume the piston is being displaced tothe left inFig. 11. under the influence ofcompressed air admitted. against itsright side. Any

excessive frictional engagement between the right.

hand bead 82 of the piston and the cylinder wall, during such movement,creates a drag tending to :pull the bead back from the normal full lineposition of Fig. 11 toward the broken lineposition of that figure. Beingformed as an integral part of the piston itself, the bead tends to swinginwardly upon such relative rearward displacement in a manner relievingthe excessiveyfrictional engagement with the cylinder wall.Consequently, the bead maintains. only relatively light engagement withthe cylinder at all times. Further, that engagement with the'cylinderinvo'lvesin all conditions, essentially single line contactbecause of the circular sectional configuration of the bead.

As will be understood, in designing a piston of the above character foruse in a certain range of pressures, it is necessary that the bead be soconstructed as to be displaceable between the illustrated full andbroken line positions by a frictional drag of just sufiicient magnitudethat optimum engagement between the piston and cylinder will bemaintained. Two factors of major importance in arriving'at this pistondesign are, first, the hardness of the rubber or other resilientmaterial from which the piston is formed, and second, the minimumthickness i (see Fig. 11) of the annular connection between thebead andthe body of the piston, as compared with the size of the bead itself. Asan example, it has been found that, for use with pressures between 60and 150 pounds, a piston formed substantially as illustrated in thefigures should pref erably be composed of rubber having a hardness of 80as tested by the Shore method.

Piston rod 80 contains an air conducting inner passage or bore 84 ateach .side of the piston, and has, at each side, a lower exhaust opening85, an upper inlet opening 86, and an opening 81 adjacent the piston,.all of which openings communicate with bore 85, At its left end as seenin Fig. 3f, the piston rod carries a projecting plug 88 having astraight sided end portion 89 received and guided by recess 12 in'theshoe. At its other end, rod 83 carries an insert against which spring Siis engaged to urge a relatively movable lug 92, corresponding to plug88, into the other recess 12 formed by the shoe. Thus, the ends of thepiston and valve assembly engage the end uprights 59 of the shoe in amanner transmitting reciprocating motion to the shoe while permittingrelative transverse movement between the shoe and. piston. assembly.

- In usingithe. illustrated sandenxair andywater: lines-stand 9d areconnected tosinletrfittings 35-and 43, and a pieceof sandin paperorcloth E4 is retained about the. bottom .of' the shoezby.

clamps 13. Depression of. valve .handle dflthen opensboth the air and'water linesto simulta neously reciprocate :the shoe relative .;to theban.- dle and discharge water :onto the surface.- being treated. In the:position.. fiFig.-3, for instance.

the left end of the piston rod is in :a position rad-- mittingcompressed air to theleftsideof' the:v

piston through the corresponding passage 23,

openings 29 and 86, bore 84, and opening 81.. At.

the same time, air to the right of the piston .is beingv exhaustedthrough the opening 81, bore 84,, openings V and 30 and passage 24 atthat side of Consequently, the. piston is being driven to the right. Asithe'pistonxnears the right 5 the piston.

side of the cylinder, the inlet: and exhaust connections are reversedtointroduce air to the right side of the piston and exhaust :itxfrom theleft, with. resulting leftward movement of the piston; Thisreciprocating motion of the pistonis transmitted to the shoe and sandingpaper through end flanges 59 of the shoe. Since the piston rod isvertically .slidable at. its ends within recesses.- '52, force exerteddownwardly againstthe-handle shoe without any tendency for. swinging thepiston from its proper position of. axial alinement with the cylinder.

I claim:

1. A reciprocating tool actuating devicecomprising a first sectionhaving a cylindrical bore, a second section extending alongside andmovable relative to said first section-and adapted to carry a workengaging element, asingle piston received within said boreof. the firstsection and adapted for powered reciprocation relativethereto, a pair oftransverse walls at the opposite ends of said bore each containing acentral axially extending opening, a pair of piston rods extending inopposite directions from said piston through said openings in the wallsrespectively, said second section. having a pair of projections extendinto locations opposite the outer ends of said rods respectively, and.engaging said second section to transmit reciprocating motion of thepiston thereto, said rods and said end walls containing fluid conductingpassages cooperating to alternately admit pressure fluid to oppositesides of said piston and thereby effect said powered reciprocation, andsaid rods having end portions outwardly beyond said transverse Walls.and en.- gaging said projections of the second section to transmitreciprocating motion of the piston site directions from said piston,said rods and.

said first section containingfluid conductingpassages cooperating toalternately admit pressure fluid to opposite sides of said piston foreffecting its powered reciprocation, and rotatable bearings. guidingsaid sections independently of the piston and rods for relativereciprocation parallel to the axis of said piston, said piston rods andsaid second section having shoulders engaging to transmit said poweredreciprocation of the piston to said'second section, said rods and saidsecond section being relatively movable transversely of said piston atsaid engaging shoulders to prevent the transmission of transverse thrusttherebetween.

- 3. A reciprocating tool actuating device comprising a first sectionhaving an inner bore, a second section movable relative to said firstsection and adapted 'to carry a work engaging element, a pistonadapted'for powered reciprocation within said bore of the first section,va pair of piston rods carried by and extending in opposite directionsfrom said piston, said rods and said first section containing fluidconducting passages cooperating to alternately admit pressure fluid toopposite sides of said piston for effecting its powered reciprocation,rotatable bearings guiding said sections, independently of the pistonand rods for relative reciprocation parallel to the axis of said piston,said piston rods having transversely extending outer end faces engagingsaid second section to transmit said powered reciprocation of the pistonto said second section, said rods and said second section beingrelatively movable transversely of said piston at said end faces of thepiston to prevent the transmission of transverse thrust therebetween,and means keying said piston rod in predetermined angular relation tosaid first section for maintenance of said cooperating passages in acorresponding predetermined angular relation.

4. A reciprocating tool actuating device comprising a first sectionhaving an inner bore, a second section movable relative to said firstsection and adapted to carry a work engaging element, a piston adaptedfor powered reciprocation within said bore of the first section, a pairof piston rods carried by and extending in opposite directions from saidpiston, means guidin said sections independently of the piston and rodsfor relative reciprocation parallel to the axis of said piston, saidpiston rods and said second section having shoulders engaging totransmit said powered reciprocation of the piston to said secondsection, said rods and said second section being relatively movabletransversely of said piston at said engaging shoulders to prevent thetransmission of transverse thrust therebetween, and a spring yieldinglymaintaining said shoulders in engagement.

5. A reciprocatin tool actuating device comprising a handle section,containing a bore, a rigid shoe section bodily movable relative to andalongside said handle section and adapmd to carry an element forengaging work, and a piston in said bore for bodily reciprocating saidrigid shoe section relative to said handle section, said handle sectioncontaining a passage adapted to conduct liquid from an inlet line to alocation adjacent said shoe section, said shoe section having a passagecommunicating with said handle passage and conducting liquid therefromto discharge onto the work.

6. A reciprocating tool actuating device comprising a handle section, ashoe section adapted to carry an element for engaging work, a fluidpressure actuated piston for bodily reciprocatin said shoe sectionrelative to said handle section, said handle section containing apassage adapted to conduct liquid from an inlet line to a locationadjacent said shoe section, said shoe section having a passagecommunicating with said handle passage and conducting liquid therefromto discharge onto the work, rotatable bearings carried by one of saidsections at opposite sides of the communicating ends of said passages,and guide means on the other of said sections engageable with saidbearings to guide the shoe section for said reciprocating motion.

7. A reciprocating power unit for a tool actuating device comprising abody having an inner cylindrical bore, a single piston received withinsaid bore and adapted for powered reciprocation relative thereto, a pairof transverse walls at the opposite ends of said bore each containing a"ered reciprocation, and said rods having planar end faces extendingdirectly transversely thereof outwardly beyond said transverse walls forengaging a movable shoe to transmit reciprocating motion of the pistonthereto.

8.'A tool reciprocating device comprising a shoe section adapted tocarry a work abrading element along a first side thereof, a handlesection extending along the opposite side of said shoe section, saidshoe section bein reciprocable relative to said handle section, a firstone of said sections including a cylinder unit and a piston unit adaptedfor fluid pressure actuated relative reciprocation, one of said unitshaving shoulder means acting against the second section to transmit saidreciprocation thereto, the efiective force transmitting portion of saidshoulder means being substantially in axial alinement with the pistonand cylinder units, and said one of the units and said second sectionbeing relatively movable transversely of said axis at said shouldermeans to prevent the transmission of transverse thrust therebetween, andbearing means guiding said shoe section for said reciprocation relativeto the handle section.

9. A tool reciprocating device comprising a shoe section adapted tocarry a work abrading element along a first side thereof, a handlesection extending along the opposite side of said shoe section, areciprocable power piston in said handle section, reduced dimensionpiston rod means carried by said piston and extending axially therefrom,said rod means having shoulders acting against the shoe section totransmit the powered reciprocation of the piston thereto, the eifectiveforce transmitting portions of said shoulders being substantially inaxial alinement with said piston, said piston rod means and said shoesection being relatively movable transversely of the axis of the pistonat said shoulders to prevent the transmission of transverse thrusttherebetween, and means guiding said shoe sec-' tion independently ofthe piston and rod means for reciprocation relative to the handlesection.

10. A tool reciprocating device comprising a body including a handlesection and a relatively reciprocable shoe section adapted to carry awork engaging element, said handle section containing a cylindrical boreand having a water jacket recess substantially directly adjacent butisolated 'from the bore, a power piston in the bore for reciprocatingthe shoe section relative to the handle section, said body containinginlet passage means for conducting liquid into said water jacket recess'to'co'ol the bore, and'said body containin discharge passage meansreceiving liquid from said recess and discharging it onto the work.

11. A tool reciprocating device comprising a handle section containing acylindrical bore and a water jacket recess extendin about andsubstantially directly adjacent the bore but isolated therefrom, arelatively reciprocable shoe section extending alongside said handlesection and adapted to carry a work engaging element, a piston in saidbore and adapted for powered reciprocation to effect relativereciprocation between" the sections, means for transmitting said pistonreciprocation to the shoe sections, said handle section containingpassage means for conducting 'cooling'liquid to said water jacket toflow thereabout and thento a location adjacent said shoe'section, andsaid'shoe section containing'passage means'receiving said cooling liquidatsaid location and discharging it onto the work.

12. A tool reciprocating device comprising a handle'sectioncontaining acylindrical bore, a relatively 'reciprocable shoe section extendingalongside said handle section, and adapted to carry a work engagingelement, a piston in said bore and adapted for powered reciprocation toeffect relative reciprocation between the sections, means fortransmitting said piston reciprocation to the shoe section, saidsections having a pair of opposed planar substantially parallel surfacesextending parallel to said bore and to the axis of reciprocation of thesections, said handle section containing a passage for conducting liquidfrom a supply line to a location at said surfaces, said shoe sectioncontaining a passage communicating with said handle passage at saidsurfaces and adapted to conduct liquid therefrom to discharge onto thework, and a seal pad received between said surfaces in engagementtherewith to prevent leakage of said liquid outwardly between thesurfaces, said pad having a planar surface engaging one of said planarsurfaces on the sections and having a bead projecting toward and engaginthe other section about said passage therein.

13. A tool reciprocating device comprising a handle section containing abore, a shoe section extending alongside said handle section, a powerpiston in said bore, a pair of piston rods projecting in oppositedirections from said piston and acting against the shoe section at theiropposite ends to transmit piston reciprocation thereto, one of said rodsincluding a main portion and a second portion carried at an end of andmovable relative to said main portion and acting against the shoesection, and means yieldingly urging said second portion of said one rodaxially away from the piston and into engagement with the shoe section.

14. A tool reciprocating device comprising a handle section containing acylindrical bore, a shoe section extending alongside said handlesection, a reciprocable fluid pressure actuated piston carried by saidhandle section within said bore and operable to reciprocate the shoesection relative thereto, a first valve carried by the handle sectionfor controlling the admission of pressure fluid to said piston andhaving a movable actuating element positioned partially at the outsideof the handle section, said handle section containing second passagemeans through which a liquid for delivery onto the work passes, a valvefor controlling the delivery of liquid through said second passage meansand having an actuating element positioned near and movable generallyparallel to said actuating element of the first valve, and a controlmember movably mounted at the outside of said handle section andoperable to simultaneously engage said actuating members and actuatethem substantially in unison.

1'5. A tool reciprocating device comprising a first section containing abore, a second section for carrying a'work engag'ing element, a pistonin said bore for relatively reciprocating said second section, a pair ofaxially spaced circular plugs in said bore at. opposite sides of saidpiston forming a pair of spaced transverse walls in the bore, said plugsandfirst section containing registering fluid supply passages, pistonrod means carried by the piston and projecting in opposite directionstherefrom through said plugs, said-rod means containing passage meanscooperating with the plug passages to control the admission of pressurefluid to the piston, and 'a pair of tubes projecting into saidregistering passages in both the plugs and first section to key themto'-' gether and conduct fluid therebetween. I

16. A tool reciprocating device comprising a first section containin abore, a second section for carrying a work engaging element, a piston insaid bore for relatively reciprocating said second section, a pair ofaxially spaced circular plugs in said bore at opposite sides of saidpiston forming a pair of spaced transverse walls in the bore, a handlemounted about the first section, said plugs, first section and handlecontaining registering fluid supply passages, piston rod means carriedby the piston and projecting in opposite directions therefrom throughsaid plugs, said rod means containing passage means cooperating with theplug passages to control the admission of pressure fluid to the piston,and a pair of tubes projecting into said registering passages in thelugs, first section and handle to key them together and conduct fluidtherebetween.

1'7. A tool reciprocating device comprising a handle section containinga cylindrical bore, a shoe section extending alongside said handlesection parallel to the bore and adapted to carry a Work engagingelement at a side opposite the handle section, a piston in said bore forrelatively reciprocating said sections. two spaced sets of rollerscarried by said handle section, said shoe section having a pair of saced tracks each having opposed walls at opposite sides of said rollersand engageable thereby to guide said sections for relativereciprocation, means mounting two of said rollers of each set to saidhandle section for rotation about spaced axes, and means mounting thethird roller of each set to said handle section between said two rollersof that set and for rotation about an axis offset from a plane extendinthrough the spaced axes of said two rollers, said two rollers of eachset engaging only one of said spaced walls of the associated track andsaid third roller engaging only the other of said track walls.

18. A tool reciprocating device comprising a handle section having aninner bore, a relatively movable shoe section extending alongside thehandle section substantially parallel to said bore and adapted to carrya work engaging element at a side opposite the handle section, a pistonadapted for powered reciprocation within said bore'of the handlesection, a piston rod carried by and extending in opposite directionsfrom said piston, said rod and said handle section containing fluidconducting passages cooperating to alternately admit pressure fluid toopposite sides of said piston for effecting its powered reciprocation,and rotatable bearings guiding said sections independently of the pistonand rod for relative reciprocation parallel to the axis of said piston,said shoe section having a pair of projections extending to locations atopposite ends of said piston rod, said piston rod at its opposite endsand said projections of the shoe section having transversely extendingshoulders engaging to transmit said powered reciprocation of the pistonto the shoe section, said rod and said projections being relativelymovable transversely of said piston at said'engaging shoulders toprevent the transmission of transverse thrust therebetween.

'19. A tool reciprocating device as recited in claim'18, in which saidbearings comprise two spaced sets of rollers carried by said handlesection, said device including a pair of spaced channel shaped trackscarried by said shoe section and each having a pair of opposed walls atopposite sides of said rollers and engageable thereby to guide saidsections for relative reciprocation, means mounting two of said rollers12 of each set to said handle section for rotation about spaced parallelaxes, and means mounting th third roller of each set to said handlesection between said two rollers of that set and for rotation about anaxis offset from a plane extending through the spaced axes of said tworollers, said two rollers of each set engaging only one of said spacedwalls of the associated track and said third roller engaging only theother of said track walls.

EARNESI' E. MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 957,336 Higgs May 10, 19101,238,062 Ekstrom Aug. 21, 1917 1,365,924 Lagerquist et al. Jan. 18,1921 1,506,219 Clark Aug. 26, 1924 1,590,353 Ekstrom June 29, 19261,700,114 Thompson Jan. 22, 1929 1,926,828 Van Berkel Sept. 12, 19331,953,534 Everett Apr. 3, 1934 1,954,489 Partlow Apr. 10, 1934 2,120,300Taylor June 14, 1938 2,211,456 Caldwell Aug. 13, 1940 2,466,584 DufiApr. 5, 1949

